Hydraulic power system



Dec. 29, 1942. c, co so 2,306,379

HYDRAULIC POWER SYSTEM Original Filed March 12, 1932) I s Sheets-Sheet 1 INVENTOR. CcwracZ fl K (bnradson ATTORNEYS Dec. 29, 1942. C; M, @NRAD ON 2,306,379

HYDRAULIC POWER SYSTEM Original Filed Match 12, 1950 s Sheets-Sheet 2 INVENTOR. C an/ad M @nraalsofl @TTORNEYS Dec. 1942. c. M. CONRADSON 7 2,306,379

HYDRAULiC POWER SYSTEM 7 Original Filed March 12, 1930 3 Sheets-Sheet} Y K \i llll ' l k} INVENTOR.

Uonrad Corlradson l z/m ATTORNEYS Patented Dec. 29, 1942 HYDRAULIC POWER SYSTEM Conrad M. Conradson, Detroit, Mich; Frederick R. Walter, administrator of said Conrad Conradson, deceased, assignor, by mesne assignments, to Oscar Christlanson, Madison,

Wis., as trustee Original application March. 12, 1930, Serial No. 435,210, now Patent No. 2,166,940, dated July 25, 1939. Divided and this application March 7 20, 1939, Serial No. 262,928

Claims. (on. 6097) My invention relates to improvements in hydraulic power transmitting systems.

This application is a division of my copending application, Serial No. 435,210, filed March 12, 1930, and issued as Patent'No. 2,166,940, dated July 25, 1939. t

The primary object of my invention is to provide means whereby the flow of a power liquid,

4 such as oil, through a driven mechanism, or motor, may have its pressure and volume regulated in accordance with speed and power requirements.

More specifically stated, my object is to provide a hydraulic system in which the pressure drop of the liquid employedfor power purposes may be controlled by a pressure regulating valve, and its volume controlled by a variable orifice escape valve, the organization being such that the rate of flow may be exactly predetermined in accordance with established engineering formulae for determining the rate ofdischarge through an aperture under a given head. My

inventionv contemplates the use of hydraulic motors of arm type, with associated supply and exhaust ducts, and any ordinary manually adiustable valve mechanism controlling the flow of the liquid in either the supply or the exhaust duct, but in addition thereto I employ a reducing valve and an associated escape valve having an orifice of variable capacity through which the rate of flow is determined by the pressure head established by the pressure regulator, thus making possible an exact control of the speed and power of a hydraulic motor.

Further objects of my invention are to devise improved valve mechanism and pressure and volume regulating mechanism suitable for accommeans for accurately regulating the viscosity of by the liquid may be circulated under a pressure presses, and otherwise satisfy the requirements of a modem machine shop for varied intermittent and continuous operations suitable to be performed under hydraulic power.

' In the drawings: 4

Fig. 1 is a diagrammatic view of a portion of -a hydraulic system embodyingmy invention,

showing the central power supply station and two machines connected to receive power therefrom.

Fig. 2 is a longitudinal sectional view of one Y or the pressure regulators employedin association .with thevalve mechanisms conveniently illustrated in Fig. 1 and used to obtain accurateto control deliveries to and from each motor and v to also control delivery to one of the pressure plishing the objects above set forth; to provide and in a volume on the high pressure side of the system, considerably in excess of the highest motor requirements and by-passed through motors to a'low pressure or return main or delivered through a pressure-regulator to a return main at the end of the supply main in a manner 'to permit continuous circulation regardless of the number of motors in use; to provide improved'means for utilizing hydraulic power in a manner similar to that in which electrical power may be used, but with a greater range of power and speed in the individual units, to drive carriages, rotate turrets, actuate tools in quick and slow movements, operate hydraulic jacks and ly controlled motor speeds.

Fig. 3 is a central vertical longitudinal sectional view of manually adjustable motor controlling valve mechanisms, one of which is used regulators disclosed in Fig. 2.

Fig. 4 is a sectional view drawn to line 4-4 of Fig. 3.

Fig. 5 is a sectional view of Fig. 3.

h Fig. '6 is a sectional view drawn to line 6-6 of Fig. 3, showing the valve in a neutral position.

Figs. '7 and 8 are similar views showing, respectively, the valve in rapid traverse and tool feed controlling position.

Figs. 9, 10 and 11 are sectional views taken respectively on the lines 9-9 of Fig. 3 to show another portion of the valve in the same posidrawn to line 5-5 tions of rotative adjustment in which it is illus-.

trated in Figs. 6, 7 and 8.

Fig. 12 is a fragmentary sectional view drawn to line l2-I2 of Fig. 6, and illustrating the port 13 as seen from the inner face of the valve chamber.

Fig. 13 is. a perspective view illustrating conventionally the means for regulating the temmay be provided with an ordinary spring actuated check valve it, which will serve asa safety .valve to open under excess pressure and allow the liquid to enter a return pipe I! which reconveys it to the reservoir ll.

At various points along the line of the main i5 branch ducts are employed to deliver the power liquid to hydraulic motors 22-23, such delivery being in each case regulated by suitable manually controlled valve mechanism, the casings 25 of which clearly appear in Fig. 1.

One of the valve mechanisms 25 indicated in Fig. 1. and hereinafter more specifically described, is employed to regulate both the delivery to and the exhaust from, a motor 22,'which has a reciprocatory piston 28 to be driven by the liquid. In one position of the controlling lever 23, the valves are addusted so that the liquid passes freely to one end of the motor cylinder 22 through a pipe 21 and exhausts from the other end through the pipe 28, and one of the valve ports, to pipes 33 and 32, and thence to the return or low pressure main II. In another position of lever adjustment, the'exhaust (and the speed of the motor), is additionally controlled by cutting of! deliveries through pipe 30 and directing the liquid through a pipe 3i connected with the casing member 33 of an associated pressure and volume regulator, the structure and mode of operation of which is hereinafter de-' scribed;

The motor indicated at 23 may be assumed to be a rotary hydraulic motor such, for example,

as a gear motor. But further description of themotors is deemed unnecessary since the structural features of the motors form no part of the invention and means for controlling the speed of operation will be the same regardless of the type of motor used. It.may be assumed, howhead 43 and forms the inner end of the cavity 44.

A cylindrical slide valve 52 is mounted within the casing member 33 and the end facing the outlet port 53 is provided with an axial bore 53, which, with the space between this valve and the head 43, forms a pressure accumulating cavity.

At the inner end of the bore 53 there is a radially extending port 54 in a position for normal registry with the inlet port 40. A coiled compression spring 55 is socketed in the cap 56 and tends to urge the slide valve 52 in the direc tion of the outlet port 50, but the pressure of the liquid admitted through the registering inlet ports 4| and 54 tends to urge the valve 52 in the opposite direction. When this pressure exceeds that exerted by the spring 55, the valve 52 will progressively close the port 4i until the flow of liquid through this port balances the out-flow permitted by the needle valve.

Therefore, the needle valve may be adJusted to precisely regulate the rate of liquid delivery, since the flow of the liquid through an aperture of a given capacity and under a given pressure will be equal at all times unless there is a change in viscosity, in whichevent a readjustment of the needle valve would be required. However, my inventionincludes means for maintaining a uniform viscosity as will be hereinafter explained.

ever, that the motor 22 may be employed-to reciprocate a boring bar 31 or any other tool carried by the turret 38 and it may also be assumed that the motor 23 may be employed to operate a drill or any other tool revoluble about a vertical axis regardless of whether such tool does or does not reciprocate vertically, as hereinafter set forth in the detailed description thereof, and each of the valve mechanisms 25 (Figs. 3, 6 and 9) has a neutral, 1. e., a fully closed position, so that when adjusted to such position by the lever 26 no liquid will be delivered to the associated motor. However, the pump. l2 may, if desired, be continuously driven by its motor 39 or from any other suitable source of power, whereby hydraulic power will be continuously available to any machine connected with the main l5. s

In order that the means for controlling the operations of the motors may beclearly understood, the structure of the regulator at 33 will now be described, after which the structure of the valve mechanism will be set forth in detail and the cooperation therewith of this and volume regulator will be explained The structure of the regulator at 33 is clearly shown in Fig. 2. A

The-cylindrical casing member 33 has a radial inlet port with which the pipe 3| communicates. Into one end of this casing member 33 a head 43 is screwed, which has an outlet cavity 44 in communication with the pipe 32 through a port 45. The head 43 carries a needle valve 48, the stem of which is threaded axially into the head at one end of the cavity 44 and has its outer end keyed to a rotatable cap 41 and secured thereto by a nut 48. The needle valve 48 seats in a conical port 50, preferably formed in a nut Iii which is screwed into the inner end of the pressure To facilitate assembly, suitable packing rings 80 are seated against the shoulders formed by a central inwardly projecting portion I of the casing member 33. The end portions of the casing member are threaded internally to receive the packing nuts 62 and I3 and on the outlet side, oppositely faced packing rin s II and 64 are preferably employed." After these parts have been assembled a head 43 and cap 53 are screwed into the respective ends of the casing 33 to complete the assembly.

Unless means are provided by key or otherwise to'prevent the slide valve 52 from rotating, this valve should have an annular groove 66 in registry with the port 34 whereby the liquid may enter the port I4 from the port 40, regardless of whether or not the ports 4| and 54 are radially aligned. The rate of flow through the port 42 will be proportional to the area oi! its own outlet as determined by longitudinal movements of the delivery or the exhaust from 3D. This main valve mechanism will.

- adjustment of the controlling lever the main valve mechanism may slide valve 52. The relative capacity of this opening as compared with that controlled by the needle valve will, of course, determine the degree voi pressure that may be built up within the cavity 53 and thus make possible volumetric control by means of the needle valve as sure is maintained in the tank l4, since the pres- 1 sure at the needle valve is regulated by its asso-v ciated pressure regulating valve 52.

, As above explained, the use of the pressure and volume regulator is dependent upon a specific 23, whereby be utilized to connect up the regulator at 33 and shut 01! direct the motor through the pipe now be described.

The casing member 25 is ported in four directions in the plane represented by the line H in Fig. 3. Each of these ports is preferably in the form of a slot, rectangular in cross section and extending longitudinally of the casing, whereby a uniform rate of shut-oi! may be obtained by a rotary plug valve 13 within the casing. It will be obvious that the eifective area of a rectilinear port will be exactly proportioned to the movement of the valve across the port from long as excess preswill progressively decrease.

'tor operation. r

. the port H, is the direct flow outlet port connected with the pipe 80, and associated with the return main IT. The two side ports 13 and H are connected to the motor and are adapted to serve as either supply or exhaust ports, dependent in any given instance on the direction of the mo- I'he rotarv valve I is preferably of the taper plug type and as clearly appears in Figs. 6, 7 and 8, it has oppositely disposed arcuate cavities and T8 in its peripheral surface and it is also provided with an axial cavity 11 from which two radial ports 19 and 80 extend to the periphery.

In Fig. 3 it will be observed that a rod 85 extends axially through the cavity II in the rotary valve 19 and is provided with an annulus which serves as a check valve 86 andnormally separates this cavity 11. from a cavity 81 of smaller diameter in communication with two radial ports 88 and 89, one of which appears in Fig. 3, but both of which are shown in Figs. 9, 10 and 11. These ports 88 and 89 are adapted for independent regbeing the capacity of the ports and connecting pipes unless the valve is carefully adjusted to only partially open the ports. Should more than one of the valves 19 be shifted to operate a plurality of motors simultaneously on rapid traverse strokes, they may not necessarily operate at equal speeds, but the motor having the lightest load will tend to take the greater portion of fluid delivered from accumulator 14. However, where the accumulator is designed with sufficient capacity, this tendency can be minimized since the faster a given motor consumes fluid the.

greater is the pressure drop in the pipes and connections leading to the motor, the pressure drop increasing as the square of the fluid velocity. Since the rapid traverse stroke is in most cases used for bringing the tool into position for beginning of actual work and requires only a small interval of time in any case, there is little necessity of insuring equalized speeds or even of simultaneous movement of a plurality of motors on the rapid traverse stroke.

- illustrated in Figs. ,8 and 11.

istry with a port 99 in communication with the pressure regulator inlet through the pipe 3|. A coiled compression spring 9| tends to hold the valve 86 to its seat on the tapered shoulder formed at the junction of the cavity II with the cavity 81, whereby delivery of liquid through the ports H and when the lever is swung upon the pivot pin 93, this rod 85 may be actuated to open the check valve 86. When the lever is swung rotatively the rotary valve 10 may be adjusted in the manner now to be described.

As shown in Figs. 6 and 9, the cavity 15 is in registry with the inlet port ll but with no other port, and the cavity 15 is in registry with the outlet 12 but with noother port. The radial ports 19 and 80, 88 and 89, are closed at their outer'ends. liquid can pass through the casing. This is the normal or neutral position.

Assuming the valve I0, controlling the deliveries to the motor 22 (Fig. l) to be in the neutral With the valve in this position no But as the tool approaches the work, the lever 16 may be reversely actuated to rotate the valve in the opposite direction (counter-clockwise) until the valve reaches the position in which it is In that position, its arcuate cavity 15 will still connect the ports II and T3 to continue the delivery of liquid to the right hand end of the cylinder 22.

But it will be observed in Fig. 8 that cavity 16 will then be in registry only with port 12. The radial port 89 will be in registry with the port H and the pipe 29 will therefore be in communication with the central or axial valve cavity II from which liquid cannot escape until the lever I6 is swung upon the pivotal axis 93 in a'plane at right angles to its above described movement of rotation, the lever being then brought to the dotted line position indicated in Fig. 3. lever movement actuates rod 85, opens the valve 88, and allows the liquid to flow from the cavity 11 into the extension cavity 81 and thence through the registering ports 88 and 90 and pipe 3| to the pressure and volumeregulator, where its pressure is regulated by the slide valve 62. and its rate of flow determined by the needle valve 48.

With a rate of flow thus predetermined by the setting of the needle valve it reaches the return duct 32 through the port 45.

By thus controlling the volume of liquid returned from the exhaust side of the piston of motor 22, the motion of the latter may be accurately controlled by adjustment of the needle valve in accordance with the tool feeding requirements of any tool carried by the turret. It will be seen that during the feeding movement oi. one motor one or more of the other motors may be actuated on feeding strokes simultaneposition in which it is illustrated in Figs. 6 and, rate of fluid consumption of all the motors is 9, it is obvious that if it is rotated in a clockwise movement to the position in which it is indicated in Figs. 7 and 10, liquid from the main I5 will be received through the pipe 20 and delivered through the valve cavity 15 and pipe 21 to the right hand end of the motor cylinder 22. Liquid ously, and all possible variations in load on one motor will have no eflfect on any other motor. This is true right up to the point where the total just equal to the total delivery capacity of the source. In other words, each regulator valve acts, when the load on a given motor falls off, to impose additional resistance on the exhaust line which in turn keeps the pressure in the supply duct from falling oil at all.

For retraction of the tool the lever 28 will first be swung to its neutral or upright position, thereby stopping the motor by closing the valve 86.-

By then swinging the lever to move the valve in a counter-clockwise direction from the position carriage 86 and tool 31, the only limiting factor in which it is illustrated in Fig. its port 15 This may be brought into simultaneous registry with through the ports 14 and pipe 22 to the left hand a of the cylinder 22. In this position of the valve it is obvious that the liquid will then be allowed to freely pass from the right-hand. end of the motor through the pipe 21, port It, and valve cavity 18 to 'port 12 and the return ducts or pipes 2| and 22 which lead to the return main all.

e If it is desired to limit the speed during the reverse operation of the motor 22, i. e., the movement of its piston to the right as illustrated in Fig. i, this can be done by stopping the movement of the lever It from neutral position in the counter-clockwise direction when the valve port ll is brought into registry with the casing port 12 and then moving the lever to an inclined position similar to that in which it is indicated by dotted lines in Fig. 3, whereupon liquid will be permitted to return through the pipe 21, ports 12 and ll, the axial cavities ll, I1. I! and II and through the pressure and volume regulator (Fig. 2).

The end of the valve casing is is notched at I and Ill (Fig. 4) to receive the lever at the intermediate stages of its rotative stroke when one of the ports II or II of the rotary valve II is in registry with its associated casing port ll or II. It is necessary that the leverbe adjusted in one of ,these positions before it can be swung to an inclined position as indicated by dotted lines in Fig. 3 and thus open valve 2' to connect up the pressure and volume regulator for control oi the speed of the motor.

From the foregoing description it will be obvious that like valve mechanisms and pressure volume regulators may be employed to control the operation of a hydraulic motor of any type, since means are provided for controlling delivery of the hydraulic fluid in volume and at a pressure to satisfy full speed requirements of the motor in either direction and to exactly control the speed of the motor by a pressure and volume regulator of the type described.

If a rotary motor is employed as indicated at 23 in Fig. l, the power liquid may be delivered to the motor through the pipe 21a and exhausted through the pipe 22a exactly as above described with reference to the pipes 21 and 22 associated with the motor 22. Also the flow of liquid through these pipes 21a and 20a may be reversed to reverse the operation of the motor 22 in the same manner that the operation of motor 22 is reversed as above described.

It may" be desirable to maintain a uniform viscosity of the power liquid in order to avoid the necessity of changing the adjustment of the needle value 46 in accordance with changing viscosity due to changes in temperature. If there is no change in viscosity or density the liquid above the desired degree. This means for controlling the temperature a and correspondingly controlling the viscosity is illustrated most clearly in the conventional diagram, Fig. 13, and is described as follows.

Where temperature control is desired, the valve' at Ill in the pipe ll may be closed and the liquid supplied to the pump through the pipe III, this pipe extending through an electrical heating chamber IN. A thermostat'at "2 may be employed to control, an electrical circuit of the heater through the lead I when the temperature of the oil falls below that predetermined by the setting of the thermostat.

If desired, or if conditions require, the thermostat may also be employed to control an electrical circuit through the coil of an electromagnetically operated valve at Ill, whereby, when the temperature rises above the desired limit the valve at Ill may be automatically adjusted. to by-pass the power liquid through a radiator indicated at I". A valve at Ill may be employed to shutoff the flow of the power liquid through pipe I08 when the valve at I" is open.

The use of thermostats to alternately control the operation of electro-heaters and electromagnets is well understood and detailed explanation and description is deemed unnecessary.

WhatIclaimis:

i. In a hydraulic power system, the combination with supply and return mains, and means for circulating power liquid through. the supply main delivery of power liquid to one of the motors. a volume controlling valve associated with each 4 of said valve mechanisms, and means for eifecting a uniform pressure drop in the pressure head of the liquid passing through said volume controlling valve, each of said valve mechanisms being adapted in one position to control the flow of the power liquid to and from the associated motor independently of pressure and volume regregulator, each motor receiving liquid at a couunder a given pressure in the-cavity 52 of the pressure and flow regulator. will at all times have an exactly controlled rate of flow past the needle valve 4 in any given adjustment of that valve. The density will not ordinarily vary where oil is used as the hydraulic agent and viscomty of ,the

position by pressure of the liquid at the outlet side thereof, and an adjustable device for restricting the outlet passage beyond the valve, whereby the speed of the motor may be automatically determined by said valve in co-operation with said restricting device to determine the rate of flow of the power liquid and thus maintain each motor in operation at its intended speed regardless of load variations at any other motor.

3. In a motor operating hydraulic system, a source of power liquid under constant pressure, a plurality of motors each having a supply duct connected to the source and an exhaust duct, valve rt? hydraulically connected with said ducts each individually controlling delivery or power liquid to and exhaust liquid from one of said motors, and regulator mechanisms individually associated 'with the valve mechanism and ducts or each motor serving to maintain the pressure in the supply duct or each motor against falling with a decrease in load on such motor comprising means forming an oriflce' ad,- justable to a predetermined size, and variable valve means associated therewith to maintain a trolled and thereby prevent the controlled motor from accepting any portion or the liquid norpredetermined drop across said orifice and responsive to pressures in one 01' the motor ducts.

to provide resistance in said duct to balance decreases in load on the motor controlled, whereby each motor will be maintained in operation when the load on another motor has decreased to a point otherwise permitting such other motor to accept liquid at a .rate equal to the combined rates of liquid flow to both motors at full load. 4. In a motor operating hydraulic system, a

. source of power liquid under constant pressure,

a plurality oi motors each having a supply duct connected to the source and an exhaust duct,

and regulator mechanisms individually associated with one or the ducts of each motor serving to maintain the pressure in the supply duct ot-each motor against falling with a decrease in load on such motor comprising means formingan orifice adjustable to a predetermined size, and variable valve means associated therewith to maintain a predetermined drop across said orifice and responsive to pressures in one of the motor ducts to provide resistance in said duct to balance decreases in load on the motor conrnally delivered by the source to another motor which at the time is fully loaded.

5. In a motor operating hydraulic system, a source of power liquid under constant pressure, a plurality of motors each having a supply duct connected to the source and an exhaust duct,

valve mechanisms hydraulically connected with said ducts each-individually controlling delivery or power liquid to' and exhaust liquid from one or said motors, and regulator mechanisms individuaily associated with the valve mechanism and ducts of each motor serving to maintain the pressure in the supply duct of --each motor against falling witha decrease in load on said motor, said regulator mechanisms comprising a regulator valve, 2. spring normally urging said valve to open position, said valve being urged toward closed position by the pressure of the liquid at the outlet side thereof, and an adjustable device for restricting the passage beyond the valve whereby a predetermined pressure drop is-maintained across said restricting device, said regulator valve being responsive to pressures in one of the motor ducts to provide resistance in said duct to balance decreases in load on the -motor controlled and thereby maintain the full source delivery available to operate another fully loaded-motor under conditions where the total source delivery is utilized to operate all the motors at full load.

CONRAD M. CO NRADSON. 

